Motorworld’s newspaper № 6
The Big Four 633 was outfitted with a one-cylinder, L-head, 633-cc engine having a physical size of 82 by 120 mm. Originally it was a belt-drive model, but somewhat later on, in 1915, it was replaced by the chain. In 1932 the right-side exhaust line was designed and next year a 4-speed gear box.
The Big Four 633 was James Norton’s favored motorcycle model. In the early 1930s he drove with it several thousand miles around South Africa hoping that fresh wind would help improve his health staying far away from his smoke-filled Birmingham. After his return to England an advanced model was created.
Some 4737 motorcycles (of the total of 100 thousand assembled) had sidecars that could carry two or three men with fighting equipment and munitions.
After WWII was over, the company went on to produce this model for 9 more years. In 1954, the production plant of Norton Motors Ltd. started manufacturing twin-cylinder motorcycles putting an end to the production of Big Four 633.
|Manufacturer||Norton Motors Ltd., Birmingham (Great Britain)|
|Years of manufacture||1938 – 1945|
|Quantity produced, units||4 737|
|Today’s value||10 549,8 $|
|ENGINE AND TRANSMISSION|
|Engine capacity, cc||633|
|Bore and stroke, mm||82 х 120|
|Engine rating||14.5 h.p. at 4000 rpm|
|Sparking||Magneto, right-side kickstarter arrangement|
|FRAME AND WHEELBASE|
|Front suspension||Parallelogram, with frictional damper|
|Wheel size||4,00 х 18 (3 wheels)|
|Ground clearance, mm||
|Seat height, mm||
|Gas tank size, l||
|Maximum speed, km/h||